More Like this

1. Plasmon-mediated dehydrogenation of the aromatic methyl group and benzyl radical formation

   https://doi.org/10.1039/D3SC05847F  

   Zhou, Jianghao; Guo, Jing; Ghimire, Govinda; Mebel, Alexander M; Chang, Shuai; He, Jin (December 2023, Chemical Science)

   A plasmon-driven deprotonation reaction of the aromatic methyl group can occur in aqueous solution under the illumination of red light. The reaction produces a benzyl radical and anion, and dimers through a self-reaction. 

   more » « less
2. The Regulated NiCu Cycles with the New ⁵⁷ Cu(p,γ) ⁵⁸ Zn Reaction Rate and Its Influence on Type I X-Ray Bursts: the GS 1826–24 Clocked Burster

   https://doi.org/10.3847/1538-4357/ac4d89  

   Lam, Yi Hua; Lu, Ning; Heger, Alexander; Jacobs, Adam Michael; Smirnova, Nadezda A.; Nieto, Teresa Kurtukian; Johnston, Zac; Kubono, Shigeru (April 2022, The Astrophysical Journal)

   Abstract During the X-ray bursts of GS 1826−24, a “clocked burster”, the nuclear reaction flow that surges through the rapid-proton capture process path has to pass through the NiCu cycles before reaching the ZnGa cycles that moderate further hydrogen burning in the region above the germanium and selenium isotopes. The 57 Cu(p, γ ) 58 Zn reaction that occurs in the NiCu cycles plays an important role in influencing the burst light curves found by Cyburt et al. We deduce the 57 Cu(p, γ ) 58 Zn reaction rate based on the experimentally determined important nuclear structure information, isobaric-multiplet-mass equation, and large-scale shell-model calculations. Based on the isobaric-multiplet-mass equation, we propose a possible order of 1 1 + - and 2 3 + -dominant resonance states and constrain the resonance energy of the 1 2 + state. The latter reduces the contribution of the 1 2 + -dominant resonance state. The new reaction rate is up to a factor of 4 lower than the Forstner et al. rate recommended by JINA REACLIB v2.2 at the temperature regime sensitive to clocked bursts of GS 1826−24. Using the simulation from the one-dimensional implicit hydrodynamic code K epler to model the thermonuclear X-ray bursts of the GS 1826−24 clocked burster, we find that the new 57 Cu(p, γ ) 58 Zn reaction rate, coupled with the latest 56 Ni(p, γ ) 57 Cu and 55 Ni(p, γ ) 56 Cu reaction rates, redistributes the reaction flow in the NiCu cycles and strongly influences the burst ash composition, whereas the 59 Cu(p, α ) 56 Ni and 59 Cu(p, γ ) 60 Zn reactions suppress the influence of the 57 Cu(p, γ ) 58 Zn reaction and diminish the impact of nuclear reaction flow that bypasses the important 56 Ni waiting point induced by the 55 Ni(p, γ ) 56 Cu reaction on the burst light curve. 

   more » « less
3. Controlling few-body reaction pathways using a Feshbach resonance

   https://doi.org/10.1038/s41567-024-02726-3  

   Haze, Shinsuke; Li, Jing-Lun; Dorer, Dominik; D’Incao, José_P; Julienne, Paul_S; Tiemann, Eberhard; Deiß, Markus; Hecker_Denschlag, Johannes (January 2025, Nature Physics)

   Abstract Gaining control over chemical reactions at the quantum level is a central goal of cold and ultracold chemistry. Here we demonstrate a method for coherently steering the reaction flux across different product spin channels for a three-body recombination process in a cloud of trapped cold atoms. We use a magnetically tunable Feshbach resonance to admix, in a controlled way, a specific spin state to the reacting collision complex. This allows us to control the reaction flux into the admixed spin channel, which can be used to alter the reaction products. We also investigate the influence of an Efimov resonance on the reaction dynamics, observing a global enhancement of three-body recombination without favouring particular reaction channels. Our control scheme can be extended to other reaction processes and could be combined with other methods, such as quantum interference of reaction paths, to achieve further tuning capabilities of few-body reactions. 

   more » « less
4. A paramedic treatment for modeling explicitly solvated chemical reaction mechanisms

   https://doi.org/10.1039/C8SC01424H  

   Basdogan, Yasemin; Keith, John A. (January 2018, Chemical Science)

   A static QM procedure for modeling solvated reaction mechanisms is calibrated using the Morita–Baylis–Hillman reaction. 

   more » « less
5. Microwave Heating Outperforms Conventional Heating for a Thermal Reaction that Produces a Thermally Labile Product: Observations Consistent with Selective Microwave Heating

   https://doi.org/10.1002/asia.201900625  

   Duangkamol, Chuthamat; Batsomboon, Paratchata; Stiegman, Albert_E; Dudley, Gregory_B (June 2019, Chemistry – An Asian Journal)

   Abstract Microwave (MW) heating is more effective than conventional (CONV) heating for promoting a high‐temperature oxidative cycloisomerization reaction that was previously reported as a key step in a total synthesis of the natural product illudinine. The thermal reaction pathway as envisioned is an inverse electron‐demand dehydro‐Diels–Alder reaction with in situ oxidation to generate a substituted isoquinoline, which itself is unstable to the reaction conditions. Observed reaction yields were higher at a measured bulk temperature of 200 °C than at 180 °C or 220 °C; at 24 hours than at earlier or later time points; and when the reaction solution was heated using MW energy as opposed to CONV heating with a metal heat block. Selective MW heating of polar solute aggregates is postulated to explain these observations. 

   more » « less